1. Field of the Invention
This invention relates generally to fuel vaporizer devices for vaporizing liquid fuel supplied to an internal combustion engine. More particularly, the invention relates to such a device which vaporizes the liquid fuel to a dry, heated vaporous state in a mixture with heated air and supplies the heated mixture to the cylinders of the engine.
2. Prior Art
Numerous attempts have been made in the prior art to more completely vaporize the liquid fuel supplied to internal combustion engines in order to reduce the pollutants discharged into the atmosphere with the exhaust from the engine, or to improve the performance and/or efficiency of the engine. Standard carburetors as commonly used on internal combustion engines use atomizing nozzles or jets which at least partially atomize the liquid fuel supplied to the cylinders of the engine. These devices rely upon mechanical breakup of the liquid droplets of fuel, and typically introduce the liquid fuel into the throat of a venturi which, due to the sudden drop of pressure in the venturi, causes the droplets to break up into small particles of liquid fuel. The small particles of droplets of liquid fuel are then supplied to the cylinders of the engine for combustion. However, the liquid particles do not burn completely and as a result various pollutants are discharged into the atmosphere with the exhaust from the engine.
Some of the prior art devices have attempted to overcome the problems discussed above by increasing the breakup or vaporization of the liquid fuel. The enhanced or increased vaporization is achieved in a number of ways, including mechanically contacting the particles or droplets of liquid fuel with rotating blades or by causing the fuel to flow through or past screens or swirl chambers and the like. Other devices use heating means to heat the fuel.
Examples of some such prior art devices are described in U.S. Pat. Nos. 1,006,244, 1,997,497, 2,254,634, 2,261,446, 2,733,698, 3,618,577, 4,022,173, 4,106,457, 4,151,821 and 4,330,492. These devices variously mix the air/fuel mixture with hot exhaust gas; use hot exhaust gas or electrical resistance elements to heat the fuel and/or air supplied to the cylinders of the engine; and/or mechanically contact the fuel to cause it to break up into fine particles. However, these devices are either relatively complicated and expensive or they achieve only partial atomization, albeit better than a standard carburetor. Some devices, such as that disclosed in U.S. Pat. No. 1,997,497 to C. N. Pogue, purport to achieve substantially complete atomization of the liquid fuel, whereby a hot, dry gas is supplied to the cylinders of the engine.